Stabilization of black cotton soil subgrade using sawdust ash and lime

This research dwells on how black cotton soil (BCS) could be stabilized and made a suitable subgrade material using sawdust, a readily and cheaply available material. Sawdust was burnt to ashes in a furnace at a temperature of 800?°C and then mixed with BCS in varying proportions of 4%, 8%, 12%, 16% and 20%. Since the trial mixes showed that the use of 16% sawdust ash gave better results, the BCS treated with optimum sawdust ash content of 16% was further stabilized with 2%, 4%, 6%, 8%, and 10% lime. Optimum reduction in liquid limit, differential free swell, plasticity index as well as optimum increase in CBR and specific gravity was achieved when BCS treated with 16% sawdust ash was stabilized with 4% lime. Scanning electron microscope images of the freshly prepared stabilized soil showed the occurrence of flocculation and agglomeration while X-ray diffraction tests on the cured stabilized soils showed the occurrence of pozzolanic reactions. It was thus concluded that treating BCS with sawdust burnt in an appropriate environment and combined with lime enhances its strength. It also offers another way to dispose of sawdust.     

Short communication: Adipocyte sizes in the digital fat pad and their relationship to body condition in dairy cows

Lameness and body condition are closely related. Recent studies have shown that cows with low body condition score (BCS) have a greater risk for developing lameness than cows with higher BCS. Among other reasons, this relationship might be related to the reduced thickness of the digital fat cushion in lean cows. The digital cushion is not a homogeneous structure but consists of different fat pads and connective tissue. We hypothesized that either high or low BCS will result in concordant adipocyte sizes in the fat pads of the digital cushion and subcutaneous tailhead fat irrespective of the localization of the latter. Right front claws were collected from 18 Holstein Friesian cows. Cows were selected according to their BCS: 9 cows with BCS <3 (low BCS) and 9 cows with BCS ≥3 (high BCS). After dissecting the horn capsule of the lateral claw, samples of the axial and abaxial fat pads were prepared for histomorphological examinations (adipocyte size measurement) and protein abundance of vascular endothelial growth factor A (VEGF-A) via Western blotting. In addition, fat samples were excised from the tailhead of all cows and used for the same purposes. Adipocyte size in tailhead fat was greater in high-BCS than in low-BCS cows. Similar differences between the BCS groups were apparent for adipocytes from the axial fat pad, although adipocytes in tailhead fat were larger than those in the digital cushion. In contrast to that in the axial fat pad and tailhead fat, adipocyte size in the abaxial fat pad was similar in cows from both BCS groups. A relationship between adipocyte size and VEGF-A protein was only confirmed for the axial fat pad, not for the other fat depots. When comparing BCS groups, differences in VEGF-A protein abundance between high-BCS and low-BCS cows were also limited to the axial fat pad, being absent in tailhead fat and the abaxial fat pad. Taken together, our results show that the fat pads from the digital cushion should not be considered uniform adipose tissue locations but rather discrete units reacting differently to fat mobilization.     

30000m~3/h氮压机轴位移增大故障分析及处理

阐述了压缩机轴位移增大处理过程,深入研究了压缩机轴位移产生的机理和分析处理方案,为设备维护、检修人员提供参考。     

Novel Bumping Process for Solder on Pad Technology

A novel bumping process using solder bump maker is developed for the maskless low‐volume solder on pad (SoP) technology of fine‐pitch flip chip bonding. The process includes two main steps: one is the aggregation of powdered solder on the metal pads on a substrate via an increase in temperature, and the other is the reflow of the deposited powder to form a low‐volume SoP. Since the surface tension that exists when the solder is below its melting point is the major driving force of the solder deposit, only a small quantity of powdered solder adjacent to the pads can join the aggregation process to obtain a uniform, low‐volume SoP array on the substrate, regardless of the pad configurations. Through this process, an SoP array on an organic substrate with a pitch of 130 μm is successfully formed.     

Adsorption characteristics of bamboo activated carbon

Dye is difficult to remove from aqueous solution with common adsorbents due to its large molecular size. Mesoporous bamboo activated carbon is utilized in the adsorption of Black 5, Red E and phenol. The adsorption performance of the carbon is experimentally examined along with the characterization of the adsorbent. The comparison of adsorption capacity of the bamboo activated carbon with that of coconut activated carbon and carbon cryogel indicates that the large volume of mesopore in the carbon helps the expansion of adsorption capacity. Microscopic observation, the measurement of pore characteristics and fitting to the adsorption isotherms are conducted in the characterization of the bamboo activated carbon.     

Isotopic exchangeability as a measure of the available fraction of the human pharmaceutical carbamazepine in river sediment

Cabamazepine (CBZ), an antiepileptic pharmaceutical compound, is a pollutant of aquatic ecosystems entering via wastewater treatment plants that is considered to be persistent to degradation. An isotope exchange technique was employed using radiolabelled CBZ as a model compound, to determine the amount of isotopic exchangeability of CBZ in river sediment. The amount of isotopically exchangeable CBZ was used as an estimate of the extent of desorption hysteresis in solution from river sediment, including a treatment where the sediment was amended with black carbon. The isotopically exchangeable CBZ was measured by equilibrating ¹²C-CBZ with sediment for 0 to 28 days followed by a 24 hour equilibration with ¹⁴C-CBZ at the end of the incubation period. The isotopically exchangeable fraction of CBZ decreased over time in the sediment, particularly following amendment with black carbon. This has important implications for the fate of CBZ, which, apart from being resistant to degradation, is constantly released into aquatic ecosystems from wastewater treatment plants. This study demonstrates the availability of a relatively quick and simple alternative to batch desorption techniques for the assessment of the available fraction of organic compounds in sediments following their release into aquatic ecosystems.     

芒硝单井油垫法注采工艺研究

针对江苏油田赵集矿区芒硝井水溶开采时存在的上溶过快、顶板保护难等开采难点,根据保护硝层顶板、控制上溶、延长高质硝水稳产期的需要,进行芒硝单井油垫法注采工艺研究,并在新投产的4口新井中成功实施。该技术不但填补了江苏油田芒硝开采的空白,而且可为周围矿区芒硝单井的生产提供有益的指导。     

EQUILIBRIUM BEHAVIOR OF KRAFT BLACK LIQUOR IN SUPERHEATED STEAM

The boiling point rise (BPR) of black liquor with solids content of 85 to 98% was measured in superheated steam. The BPR for 85 and 95% solids content liquor is 28 and 52°C, respectively. A surprisingly large amount of liquor swelling occurs in this environment. A swelling mechanism is proposed.     

Basic investigation of noncontact transportation system for large TFT-LCD glass sheet used in CCD inspection section

Recently, thin film transistor liquid crystal displays (TFT-LCDs) have been successfully applied to desktop personal computer (PC) monitors and televisions. Higher resolution and larger mother glass sheets have been required for television displays in particular to reduce costs and improve production efficiencies. To handle the increasing resolution and mother glass size, high-speed inspection processes for detecting defects in TFT arrays using charge coupled device (CCD) cameras are becoming very important. Therefore, a noncontact transportation technique for the high-speed inspection section is necessary, to avoid damage to the glass sheet during the inspection process. In addition, high-speed CCD cameras with high resolution, large magnification and shallow focus depth are usually used in the inspection process. Accordingly, it was reported that fluctuations of less than 20 μm in the floating gap of the LCD glass sheet were required. We have used a 240 mm square LCD glass sheet as the first step of this study and an air-pad system using porous metal was investigated to support the glass sheet. The influence on the flatness of design parameters such as the nonuniformity of the permeability of the porous air pads and the appropriate combination of supply and exhaust pressures were investigated numerically for a glass sheet that was quiescently supported by the proposed air-pad system. Moreover, the numerical results are compared with experimental results to verify the validity of the numerical predictions. We found that the flatness of the glass sheet of less than 15 μm could be achieved experimentally with a floating gap of around 30 μm by using the proposed air-pad system.     

导热垫片导热性能的影响因素分析

分析硬度以及测试条件对导热垫片导热性能的影响。结果表明:随着硬度的增大,导热垫片的导热系数减小,热阻增大,适宜硬度为70度;随着测试压力的增大,导热垫片的导热系数增大,热阻减小,适宜测试压力为345 kPa;随着测试温度的升高,导热垫片的导热系数增大,热阻减小,适宜测试温度为80℃;减少导热垫片内部气体空穴,能够增大导热粉体接触几率,有助于改善导热垫片的导热性能。